This invention relates to quick-action nuts, fasteners and couplers and, more particularly, to anchor nuts and couplers for fastening reinforcing rod, especially in environments in which high loads and/or torques are applied to nuts, fasteners, and couplers.
In many applications of reinforcing rod, commonly referred to as "rebar," it is desirable to have available accessories, such as nuts and couplers, with which reinforcing rods can be fastened together or to other structures. For example, reinforcing rod is often used in tunnel wall, mine, and slope stabilization and/or soil anchoring systems. The reinforcing rod is inserted and/or grouted into the rock or soil to be stabilized; an anchor plate or bearing plate is then fitted around the projecting reinforcing rod and placed against the slope or wall to be stabilized and held in position with, for example, a clamp applied to the projecting end of the reinforcing rod. While such systems are effective, their assembly is difficult due to the heavy reverse loading of the clamps, and is extremely labor intensive.
Some of these difficulties may be reduced through the employment of helically threaded reinforcing rod systems which include large, threaded "nuts" that may be screwed on to the ends of the reinforcing rod and, for example, tightened against the anchor plates. Helically threaded reinforcing rods and systems are disclosed, for example, by Finsterwalder, U.S. Pat. No. 3,292,337; Finsterwalder, et al., U.S. Pat. No. 3,561,185; and Tani, U.S. Pat. No. 4,056,911. Although such systems have greatly increased the number of applications of reinforcing rod, known nuts for use with helically threaded reinforcing rod generally have the disadvantage of requiring a great many revolutions at the nut or other fastener on the reinforcing rod before the fastener is brought into the desired, locked position on the threaded reinforcing rod. Such processes can be time consuming and inefficient.
Quick-action fasteners for screws and bolts are known. See. e.g., Okada, U.S. Pat. No. 4,083,393; Fullerton, U.S. Pat. No. 4,378,187; Beswick, Great Britain Patent No. 590,430; Schertz, U.S. Pat. No. 3,352,341; Jansen, U.S. Pat. No. 2,896,496; Desbrueres, U.S. Pat. No. 2,021,051; and Norwegian Patent No. 72,788. Heretofore known quick-action fasteners have been designed for and intended for use with relatively light-duty screws, bolts, and the like, and fail under the loading required for successful use in such high load and/or high torque environments such as those encountered in applications of reinforcing rod systems. Such known fasteners are adapted exclusively for use with helically threaded shafts and for convenient removal therefrom by a quick release mechanism or by "unscrewing." In addition, the complexity and hence manufacturing costs of known quick-action fasteners are typically quite high.
A second application in which reinforcing rods are desirably coupled together or those in which long links of reinforcing rods are necessary as, for example, large prestressed concrete platforms, walls, and the like. Since it is generally inconvenient to manufacture, ship, and/or assemble arbitrarily long lengths of reinforcing rod, it is necessary that shorter links of reinforcing rod be coupled end-to-end. The ends of the reinforcing rods may be wired together, welded together (see Gelfand, U.S. Pat. No. 3,554,270) or clamped together (see Gelfand, U.S. Pat. No. 3,694,012 and Miles, U.S. Pat. No. 4,362,423). In addition, reinforcing rods which are helically threaded over their entire lengths or over relatively short end sections may be screwed together with an appropriate fitting. See, e.g., Majewski, U.S. Pat. No. 3,782,839. Each of these known systems for coupling reinforcing rods end-to-end are labor intensive, requiring considerable manual effort to assemble, and frequently require specially manufactured, machined and/or threaded reinforcing rod. These disadvantages are particularly acute when it is desired to couple reinforcing rods end-to-end in a vertical orientation; the clamping, screwing, or other assembly operations may then have to be performed relatively high in the air. Also, the complexity and hence manufacturing costs of such systems are typically high.